Virtually the worst diagnosis a patient can hear is: “You have HIV.” The amount of global suffering from this disease is inconceivable, made worse by the knowledge that drugs will only slow the disease, not arrest it or clear it from the patient’s body. Because of the heinous nature of HIV and subsequently, AIDS, the U.S. has poured millions into research as well as help for those facing it overseas.

In 2003, President Bush began PEPFAR, or the President’s Emergency Plan for AIDS Relief. With this program, Bush initially funded HIV drugs to 50,000 people in Africa. As of 2008, the humanitarian budget and aid has expanded to include just over 1.7 million people. This helped a large number of people but at a cost of $15 billion. Bush wants to increase this funding by 100% to $30 billion. In June, the Senate debated a bill that would increase the funding beyond this to $50 billion. The House of Representatives passed the bill in April. Bush and the supporters of increased aid hope that the extra funding will allow three to five million people infected with HIV, malaria and tuberculosis to acquire treatment. Four times this many would be taught disease prevention in hopes of stemming the tide of HIV victims before they become infected. According to Dr. Premlata Shankar, a scientist developing a type of HIV vaccine, 33 million people are infected with HIV worldwide, all of whom could potentially benefit from such a vaccine.

Developing an HIV Vaccine

In the August 22 issue of Cell, Dr. Priti Kumar describes a new way in which HIV could be prevented from replicating in its victims. Viruses like HIV work by entering a host cell, taking over the cell machinery to make the proteins necessary to replicate itself and then bursting the cell open (lysis), releasing the new viral particles to infect other cells. In the case of HIV, the virus enters T-cells, replicates and then destroys the T-cells upon lysis of the cell. The reason this is so problematic is that the T-cell is the foundation upon which the immune system is based. If the T-cells are destroyed and the cell count drops, the immune system is handicapped and unable to fight off other secondary infections, such as pneumonia or the common cold.

With current technologies, according to an interview given by Shankar to Nature, “a combination of retroviral therapies allow patients to control the infection, [but] the virus is not eradicated…rather [it] persists…in the cells.” What Kumar and his associates present is a way to shut down the virus all together and do it directly in the human host, which others have been unable to accomplish. Kumar’s technique uses small interfering RNAs (siRNA) to arrest the virus.

Going back to biology class, genes are made of DNA. DNA is turned into RNA, which is turned into proteins. Proteins do the majority of work in any organism. By using siRNAs, the RNA is bound up and unable to make proteins. If the virus cannot make proteins, it cannot replicate, cannot take over other cells and cannot harm its victim. These siRNAs are small, yet they throw a huge wrench into the viral life cycle, arresting it.

Shankar speculates that if people can be injected with these siRNAs and become infected with HIV at a later date, the siRNA would prevent the HIV from establishing itself and causing disease. This would allow large populations to be vaccinated, in a way, against a currently incurable virus. Something like this still has extensive testing to complete, and Shankar believes more toxicology studies, at the very least, need to be done in larger animals before considering human trials.

Far-Reaching Implications

The application of technology such as this has far-reaching implications. siRNAs need not only be used for HIV; they could be used for almost any disease. As long as the disease of interest has RNA, it could be halted with siRNAs, given enough time, money and research. Every day it seems as if new genes are being found that are specifically expressed during diseases such as Alzheimer’s and cancer. If the highly specific RNAs made from these genes could be shut down, it is feasible that the disease itself could be disabled, allowing the patient to live a long, healthy life. If this occurs with HIV, then it may be possible to see the saving of billions of U.S. dollars normally spent on HIV drugs, which only manage such diseases rather than cure them.